“Because our species’ time on Earth is very likely to be finite, we should be doing everything we can to colonize nearby worlds — particularly Mars — to increase our odds of survival. Putting a permanent colony of humans on Mars would be an insurance policy against a civilization-ending catastrophe here at home, like an errant comet or an accidental outbreak of thermonuclear war.”

[Astronauts] have the strength to walk, but it takes more concentration, as they haven’t sent those neural commands in quite the same way, lately. When we walk, we essentially lean forward, start to fall, and use our legs to stabilize. Newly returned astronauts have to think about their gait.